Roof button faintly lit?

J

junglist

Member
Hi all,

In-between the roof up / roof down buttons there's 2 little boxes that light up red.

Am I right in thinking that these should be totally off, as when my ignition is off and key out I can see the top one is still backlit a faint red?

I seem to have a drain on the battery somewhere, if I leave it more than a day or two without driving it it can struggle to start so wondered if this could be it?
 
They shouldn't be on. Could be related to your battery drain but sounds very strange indeed. To check for parasitic current draw, get a basic voltmeter and measure the voltage drop across all the fuses in the fusebox behind the glovebox (each fuse has a couple of test points on the top so you can measure across them in situ). Any volt drop over the below indicates a fault current flowing somewhere:

5A fuses - 2mV (indicates approx 100mA flowing through it)
10A fuses - 1mV (indicates approx 130mA flowing through it)
20A fuses - 1mV (indicates approx 300mA flowing through it)
30A fuses - 1mv (indicates approx 500mA flowing through it).

This should be done with the car in sleep mode, i.e. all accessories off, car locked with you inside (so press lock on keyfob twice to disarm interior microwave sensors) and wait 10 mins.

Also don't forget there are some other larger fuses under the bonnet next to the ECU bucket...
Z4 under bonnet fuses.jpg
 
It's also worth bearing in mind that if your battery is very old it may be stuffed and have very low capacity so even a small drain is discharging it. Defo consider a new battery if that's the case before you do anything else.
 
Thanks mate, as soon as it drys up I intend on getting out with a multimeter. I know there's an iPhone connection and a Gaptech module installed so it'll be worth giving those a once over.

I left it for a month recently whilst I went away and came back to a flat battery, I'd charged it up with my CTEK trickle charger but over the last couple weeks I've had this sluggish starting - maybe down to short trips with heaters / lights on showing the weakness in the battery. Might be worth sticking the charger on again in recondition mode?
 
Don't go any further until you have replaced the battery. I'd recommend this... https://www.ebay.co.uk/itm/123343574911?ul_noapp=true

Problem with lead acids is if they are allowed to go down below 11V the plates get sulphated within a matter of days. Hard to know how sulphated it got over the month you left it but if it was down below 11V for even a week it will be stuffed.

The recondition mode can only restore very lightly sulphated batteries (maybe ones that have been discharged for 24 - 48 hrs), any more than that and the plates will be beyond the point of no return.

The Z4 is very sensitive to battery condition - you get all manner of electrical gremlins popping up when the battery isn't great.
 
Have a Gaptech in mine - no lights whatsoever on those buttons. Probably wouldn't worry too much about it unless it's related to your battery drain issue.
 
Sorry for dragging this up but do any of those fuses in the ECU fusebox power the camshaft sensors? I found a link somewhere saying they do but that there are only 5 fuses in it.
 
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